Sitepu, Dora Wahyuni Br, and Indawati Lestari. “Pengaruh Kualitas Produk Dan Harga Terhadap Loyalitas Pengguna Smartphone Vivo Studi Kasus Siswa SMA GKPI Padang Bulan Medan”. Innovative: Journal Of Social Science Research 4, no. 4 (August 12, 2024): 9819–9831. Accessed May 31, 2026. https://j-innovative.org/index.php/Innovative/article/view/14352.